The Cairo Ring Road is the most important freeway of the Greater Cairo metropolitan area in Egypt. The ring road encircles large parts of the cities of Cairo and Giza, including Cairo International Airport. Construction began in the late 1980s. It was originally planned to surround the greater Cairo region in 3 of its 4 sides, but part of the road remains unbuilt because the original route took it very near the Giza pyramids, an area which has been on the UNESCO's World Heritage List since 1979. It had two purposes: stopping the urbanization of arable lands, and reducing Cairo's traffic.